1. Technical Field
The present disclosure generally relates to firearms. More specifically, the present disclosure relates to a magazine for firearms.
2. Description of Related Art
In the context of firearms, a magazine is an ammunition storage and feeding device within or attached to a repeating firearm. The magazine functions by moving the ammunition cartridges stored in the magazine into a position where the cartridges are loaded into the chamber of the firearm. In order for fresh rounds of ammunition to be reloaded to the firearm reliably, each ammunition cartridge needs to be in a specific angle and position aligned with the firearm barrel so that it can be rammed into the barrel by the firearm action devices, e.g., the rifle bolt or handgun slides. To ensure such feeding process proceeds smoothly, the firearm magazine is designed to provide each round of ammunition with full support within the magazine. Typically, a spring inside the magazine pushes the ammunition against the magazine lip securely so that the ammunition will align axially with the barrel at the designed angle and position.
For the ease of ejection after firing, ammunition cartridges, especially rifle cartridges, have various tapering design on the casing. Due to the material used for the casing, some ammunition cartridges have larger tapering angle than others. There is one dubbed as 7.62×39, also known as M43 or 762 Russian, which has one of the largest case tapering. Another popular caliber, which is dubbed as 223 Remington, has one of the smallest case tapering. The casing of the M43 ammunition and the casing of the 223 Remington ammunition have different tapering angles. The M43 ammunition cartridges are typically stacked inside a magazine in order to maintain full support of each ammunition cartridge. The 223 Remington ammunition cartridges are typically stacked inside a magazine in order to maintain full support of each ammunition cartridge. Given the tapering angle of the casing, the stack of M43 ammunition cartridges and the stack of 223 Remington ammunition cartridges appear to have a “bent” shape although the stack of M43 ammunition cartridges has a more pronounced “bent” shape given the relatively larger tapering angle of the M43 ammunition casing. Accordingly, the design of the magazine may need to adopt the “bent” shape. An AK style magazine is typically a banana shaped magazine. There is, however, one disadvantage associated with this kind magazine. As the whole magazine has a banana shape, it has to be mounted onto a firearm with a rotational action. As a result, it is not easy to drop such a magazine by its own weight when the magazine is empty.
On the contrary, rifles such as AR15 use a STANAG magazine that utilizes a straight-bent-straight design so that the end that has the feeding lip has a straight potion and can be inserted into the rifle's straight magazine wall. When the magazine catch is released, the magazine can be dropped out of the rifle by its own weight. This allows the firearm operator to insert a loaded magazine back into the firearm with relatively less time compared to the case with the AK47 style magazine. Although the time difference may be seconds or fractions of a second, such time difference could mean a difference of life and death in the battle field.
However, such straight-bent-straight design has a potential problem. Since the ammunition has a tapered casing (albeit small), individual ammunition cartridges could be separated from one another as the ammunition cartridges are stacked into columns inside the straight potion of the magazine. For example, when stacked in the STANAG magazine, the M43 ammunition cartridges and the 223 Remington ammunition cartridges could be separated from one another at the neck area, while being in contact with one another at the tail area. This kind of freedom in movement may cause the ammunition cartridges to be jammed inside of the magazine and stop the firearm from continuous firing. For AR15 rifles, the standard ammunition used has a very small tapering on its casing. Together with the clearance tolerance between the magazine wall and the follower, the follower can be tilted slightly to compensate for the ammunition tapering effect described above. However, such tilting can only be allowed in a very small scale because excessive follower tilt in itself can introduce jam inside the magazine. In fact, some non-tilting follower designs are in place specifically to limit the excessive tilt of the follower.
As AR15 rifles are among the most popular rifles in the civilian market, ammunition cartridges of different calibers are available for the AR15 rifles. Consequently, ammunition cartridges with casings of various tapering angles have to cope with the straight magazine wall design of the AR15 rifle. Those ammunition cartridges with casing of smaller tapering tend to easily adapt to the AR15, also known as STANAG, standard shaped magazine. However, for ammunition cartridges with casing of larger tapering, a user may have trouble in finding reliable magazines, especially for large capacity magazines. Among those, the casing of M43 has one of the biggest tapering angles. It is the standard ammunition for AK47 and its military surplus is abundant. There are some AR15 rifles manufactured in this caliber. However, due to its large tapering on the casing, large capacity magazines are hardly available.
This dilemma may, to some degree, be addressed by either of a couple of approaches. As a first, do-it-yourself approach, one may weld two halves of a magazine together, with the upper half being from a STANAG standard magazine and the bottom half being from an AK47 banana shaped magazine. As a second approach, a commercially-available new magazine has been developed based on the above-mentioned idea. This perhaps is the most reliable magazine for the AR15 rifles in the 7.62×39 caliber. However, since the follower of this magazine is the same non-tilting design used in the standard STANAG magazine, the ammunition cartridges within the straight-wall portion of the magazine are still not fully supported. Hence, in some circumstances, such as shooting when moving or shooting on a moving platform, the extra momentum created by the motion might tilt the ammunition slightly with the ammunition head pointing down and cause the firearm to jam.